<script>
    // let obj = {}
    // function Person() {
    // //     var this = {
    // //         name: 'Tom'
    // //     }
    // //     this.__Proto__ = Person.prototype
    // //     return this
    //     this.name = 'Tom'
    // }
    // let p = new Person()

    //[[Prototype]]   __proto__

    // Person.prototype.lastName = '张'

    function Grand() {
        this.name = '三'
    }
    
    function Father() {
        this.age = 40
    }

    Son.prototype = new Father()
    Father.prototype = new Grand()
    function Son() {
        this.like = 'coding'
    }
    let son = new Son()
    // console.log(son.like);
    // console.log(son.age);
    console.log(son.address);
</script>